In the manufacture of fabric products such as clothing, it has long been the practice to sew the exposed edges of the fabric workpiece and render a neater appearance while also preventing fraying. In at least one type of operation, a separate, relatively narrow strip of fabric material is folded over the edge of the fabric workpiece and stitched in place to provide a hem.
Folding and alignment of the hem material has heretofore been accomplished by means of a folder attachment device. Prior art folder attachment devices generally comprise a fixed chute positioned adjacent the needle plate to render a continuous fold along the longitudinal axis of the hem material as it is conveyed through the chute.
These so called static folders have not been entirely satisfactory. A conventional sewing machine is designed to automatically advance a workpiece into position underneath the sewing needle by means of a reciprocating toothed device known as a feed dog or feeder. Because prior art folders operate independantly of the reciprocating feeder, the hem fabric is not advanced with the workpiece. The result is uneven or bunched hemlines and a defective finished product.
Up to now, the only way to minimize these problems was to slow down the stitching operation and thereby ensure the careful alignment of the workpiece and folded hem prior to stiching. As is apparent, this approach raises labor costs and requires a highly skilled operator. Producing a neat hemline with static folders has therefore remained a vexing problem in the industry.
The present invention remedies the problems associated with the prior art by providing a dynamic folder attachment device adapted to reciprocate with the sewing machine feeder causing the hem material to advance in proper alignment with the workpiece prior to stiching.